Substance abuse is both dangerous and highly prevalent in collegiate student athletes (SAs), leading it to be considered a Public Health Concern by leading researchers in the field. Although treatments have yet to evidence reductions in substance use in SAs diagnosed with substance abuse or dependence, Family Behavior Therapy offers great promise. In the proposed study we will evaluate the efficacy of this intervention in a controlled trial involving 157 SAs who are referred for problems associated with drug and/or alcohol use. FBT will target (a) illicit drug and alcohol use, (b) risk of HIV and STDs, (c) sport performance, and (d) co- morbid psychiatric problem behaviors. The controlled comparison will be conducted between FBT and treatment as usual (TAU), and include (1) utilization of a psychometrically validated structured interview to formally diagnose substance abuse and dependence; (2) standardization and uniformity of treatment; (3) objective biological methods to assess the presence or absence of drug use, (4) psychometrically validated measures to assess illicit drug and alcohol use frequency, clinical problem behaviors, problems in the relationships of SAs with peers, coaches, family and teammates, co-morbid psychiatric symptoms; and risk of HIV/STDs; (5) examination of the efficacy of FBT, as compared with TAU, utilizing assessors who are blind to treatment assignment (pre/post), and (6) 4-month follow-up to assess durability of study findings. Outcome data will be analyzed using repeated measures multivariate analyses, intent to treat will be used to manage missing data, and multi-level models will address potential homogeneity of error variance resulting from nesting or clustering of data. Participants who are assigned to FBT are expected to demonstrate significantly better outcomes than participants who are assigned to TAU from baseline to post-treatment, and from baseline to 4- mo. FU, in 1) substance use (alcohol and illicit drug use frequency, presence/absence of drug use), 2) risk of HIV/STDs, 3) co-morbid psychiatric symptoms, 4) problems interfering with sport performance, and 5) quality in relationships with teammates, coaches, peers and family. Controlled evaluation of an evidence-supported substance abuse treatment program in SAs would be a significant scientific advancement, providing mental health professionals with an evidence-based health care option for this vulnerable population. The proposed study is expected to lead to a substantial paradigm shift in 1) development of substance abuse treatment within the burgeoning field of clinical sport psychology, 2) adoption of family-based models when treating substance abuse in campus counseling centers, and 3) establish a base in which to apply these concepts to new fields.